Installing a cabinet adjacent a wall often requires a spacer or a trim strip to fill a gap between the wall and cabinet. The gap may arise, for example, because the edge of the cabinet is not parallel with the wall, because the wall or cabinet edge is not plumb, or simply because the cabinet is sized to be slightly shy of the wall. In the past, it was necessary to fabricate custom filler or trim strips to contour to the wall, span the gap between the wall and cabinet, and thereby fill or cover the gap. Fabricating such filler and/or trim strips is time consuming and can require substantial skill to scribe and conform the filler strip to the contours of an uneven wall. Accordingly, a need existed for a cabinet filler strip that self-adjusts to virtually any gap size and configuration and requires little skill to install.